A new relation between the intrinsic viscosity and the molecular mass of polymers derived from the blob model: determination of the statistical segment length of flexible polymers

Polymer ◽  
2001 ◽  
Vol 42 (3) ◽  
pp. 897-901 ◽  
Author(s):  
A Dondos
Keyword(s):  
Molecular Mass ◽  
Intrinsic Viscosity ◽  
Segment Length ◽  
Flexible Polymers ◽  
Statistical Segment ◽  
Model Determination ◽  
Blob Model

Unperturbed dimensions of polymers revisited through the blob theory: the viscometric expansion factor

e-Polymers ◽  
2013 ◽  
Vol 13 (1) ◽  
Author(s):  
Anastasios Dondos
Keyword(s):  
Molecular Mass ◽  
Intrinsic Viscosity ◽  
Graphical Representation ◽  
Original Equation ◽  
Expansion Factor ◽  
Statistical Segment ◽  
Macromolecular Chain ◽  
Unperturbed Dimensions

Abstract Plotting log([η]/M1/2) versus log(N/Nc) where [η] is the intrinsic viscosity of the macromolecular chain of molecular mass equal to M and N/Nc is the number of blobs of which this chain consists (N: the number of statistical segment of the chain and Nc : the number of statistical segment of one blob), we obtain the unperturbed dimensions parameter of the blob, Kθb. This graphical representation in this article is based on a modified, original equation of Han [6] based on the blob theory. The obtained value of Kθb for a given polymer, dissolved in a good solvent, is lower than the unperturbed dimensions parameter, Kθ, obtained for the same polymer in the Flory’s theta conditions. Having Kθb < Kθ we obtain for the viscometric expansion factors of a polymer, based on Kθb or Kθ, αηb > αη. With the obtained values of αηb we find αηb3/αs2αH ≈ 1, as predicted by Weill and des Cloizeauz [1], where using αη we obtain αη3/αs2αH ≈ 0.85 (αs and αH are the static and dynamical expansions factors).

Viscometric determination of the statistical segment length of wormlike polymers

Polymer ◽  
1998 ◽  
Vol 39 (17) ◽  
pp. 4155-4158 ◽  
Author(s):  
C. Gans ◽  
J. Schnee ◽  
U. Scherf ◽  
G. Staikos ◽  
E. Pierri ◽  
...  
Keyword(s):  
Segment Length ◽  
Statistical Segment

New approaches for the determination of dextran in the sugar production process

2018 ◽  
pp. 138-146 ◽  
Author(s):  
Karin Abraham ◽  
Eckhard Flöter
Keyword(s):  
Molecular Mass ◽  
Mass Distribution ◽  
Molecular Mass Distribution ◽  
Molecular Size ◽  
Mass Variation ◽  
Negative Effects ◽  
New Approaches ◽  
Precise Knowledge ◽  
Enzyme Application

The presence of polysaccharides in cane and beet raw juices causes several negative effects during the sugar manufacture. These are usually mitigated by enzymatic decomposition of dextrans. Such effects not only depend on the content, but also on the molecular mass distribution. This means that the different dextran fractions specifically affect the process. An accurate process control hence requires the most precise knowledge about the existing content and the molecular mass distribution present. A detailed understanding of the specific processing problems and also a targeted enzyme application hence requires the determination of a total dextran content and also its characterization including the differentiation between the different dextran fractions. An accurate analytical tool which equally satisfies industrial applicability is still lacking. To improve on this situation, two new approaches for the determination of dextran were developed and benchmarked against the commonly used and established Haze Method, which is rather inaccurate and also sensitive to molecular mass variation. The two new approaches are both based on polarimetry. These two methods indicate to be superior over the Haze Method with respect two molecular mass variation and hence enable the determination of a broader molecular size range including also low molecular mass dextrans.

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